The present invention relates to a transmission device and its component, and more especially, to an inner gear ring with variable tooth-number, the method of varying the tooth-number, and a variable transmission for vehicle composed of the inner gear ring with variable tooth-number.
There are two types of transmissions: variable transmissions and continuously variable transmissions. Continuously variable transmissions can keep the motor in optimal working condition all the time so as to make the overall efficiency higher than the variable transmission. The existing continuously variable transmissions CVT, IVT both transfer power depend on friction, so they are inapplicable to high power, heavy-duty vehicles or machines. Moreover, due to the presence of abrasion, the service life is shorter than that of variable transmission. In the existing art, the variable transmission generally includes no more than 16 shift gears. With more shift gears, the structure becomes more complicated, and volume, weight and cost are higher. Furthermore, a clutch is required when shifting, and power interruption and loss may take place during shifting, so it is preferably not to design too many shifts.